9921212187 has 32 divisors (see below), whose sum is σ = 13695811584. Its totient is φ = 6384873600.

The previous prime is 9921212177. The next prime is 9921212237. The reversal of 9921212187 is 7812121299.

It is not a de Polignac number, because 9921212187 - 2¹¹ = 9921210139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9921212107) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3239637 + ... + 3242697.

It is an arithmetic number, because the mean of its divisors is an integer number (427994112).

Almost surely, 2^9921212187 is an apocalyptic number.

9921212187 is a deficient number, since it is larger than the sum of its proper divisors (3774599397).

9921212187 is a wasteful number, since it uses less digits than its factorization.

9921212187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3419.

The product of its digits is 36288, while the sum is 42.

The square root of 9921212187 is about 99605.2819231992. The cubic root of 9921212187 is about 2148.7616584020.

The spelling of 9921212187 in words is "nine billion, nine hundred twenty-one million, two hundred twelve thousand, one hundred eighty-seven".